In Vertical FET (VFET) technologies, the height of the fin portion of the VFET is used as a channel region, where a source region is formed on the base, on a lower portion of the fin structure, and a drain region is formed on a top portion of the fin structure (or vice versa). The height of the fin structure is fixed because the gate channel defines the process. Accordingly, the height (e.g., width) of the VFET will dictate the channel length of the device, as current flow will be along a height of the VFET. For example, in VFET technologies, the type of device, e.g., long channel devices (e.g., gate length >100 nm), medium channel device (e.g., gate length of about 30 nm to 80 nm), “Wimpy” device (e.g., gate length of about 15 nm to 20 nm), etc., is dictated by the fin height.
In order to change the type of device in VFET technologies, the formation of the fin, e.g., height, needs to be adjusted. Although it is possible to change the height of the device based on the technology node, e.g., channel length, it is impractical if not impossible to form different types of devices on a single chip. This is due to the complexity of trying to alter the heights of different fins on the same chip. The cost and manufacturing time would significantly increase, while yield would significantly decrease.